<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>02_变量与常量</title>
</head>
<body>

<script>
    var a = 10;
    var b = "你好";
    var c = true;
   console.log(a,b,c);
    console.log(typeof a, typeof b, typeof c);

    a = 3.14;
    console.log(a);
    a = false;
    console.log(a);
    var a = '你好';//变量可以重复声明
    console.log(a);

    let x = 10;
    console.log(x, typeof x);
    x = 3.14;
    console.log(x, typeof x);
    //  let x = true;
    // console.log(x, typeof x);//let不可以重复声明

    const y = 10;//常量不可以重复声明
    console.log(y, typeof y);
    // y = 3.14;//常量不可以重新赋值
</script>
</body>
</html>